Possible Destination for an interstellar cruise ship?

[Flyndaran]

Originally Posted by malloyd

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The [superlative] Whatzis - the biggest, oldest, most famous, most visited, least visited... whatever - those are always popular, but not really that [different]. Alien biospheres, which have stuff you haven't seen before, at least in the details, seem like your best bet.

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That does seem the best bet for a setting grounded in a little bit of realism.
Then that leads into what biosphere oddities would be interesting for tourism.
Low G worlds with strange possible "impossibly" large life forms sounds perfect for tourists. High G worlds would only work if tourists have access to superscience gravity nullifying tech.